How the "SpamThru" trojan works

Secureworks has published the analysis of a (the?) central control server of the SpamThru trojan. Besides the fact that I would dearly love to learn more on how Spamhaus managed to identify the control server, the analysis has some proof about things we previously only could speculate about:

• Spammers managed to increase the quality of their lists. While I have observed this by eg the decreasing number of invalid recipients, Secureworks’ analysis proofs that some address lists have been stolen from unsecure webservers (by simply copying complete database dumps).
• The botnet had (has?) a size of about 73’000 computers. Even when basing on cautious assumptions, such a botnet can send out messages in the order of magnitude of 10^9 per day (“billions” for americans, “milliards” for the rest of the world).
• Most infected machines suffer from multiple diseases—from poor patching and updating cycles (only half are on a more-or-less up to date Windows release) to other malware being present.

Are you sure that your Windows machine is not part of the botnet?